The invention generally relates to tag tracking systems. In particular, it relates to a radio frequency identification (RFID) tag tracking system which tracks tags at several successive points and uses the tracking information to control a business process, such as a product supply chain. Furthermore, the invention relates to the use of such tracking information for adjusting the handling of the products during the supply chain and for varying the supply of additional products to the supply chain.
RFID tags have been used to track the location of products or other physical objects. As the cost of RFID tag systems continues to decrease and as system accuracy continues to improve, RFID tags are being used to generate information to assist in the handling of products carrying the tags. Each tag has a unique electronic product code (EPC) which can be read at successive points along a supply chain to provide information which is used to determine key performance indicators (KPI) of the chain.
Two terms are used in conjunction with KPIs: accuracy and precision. For RFID systems, accuracy represents the ability of the RFID equipment to read the tag's electronic product code (EPC) every time. Precision represents the sharpness of the tag read accuracy definition. Since the tag read accuracy is a basic formula (total actual reads/total expected reads), the precision is an important aspect, i.e., how you apply the calculation at each read point.
Because of variations in precision, a system which has several successive read points may have poor reads at some points which result in missing data. There have been some attempts in the past to infer missing data to increase precision. Other attempts at increasing precision ignore missing data and rely on good data only. There is a need for RFID systems which have increased precision so that the resulting information can be relied upon to adjust business processes monitored by the RFID systems.